There are a variety of ways to hitch a trailer to a tow vehicle. For example, bumperpull, ball and socket, fifth-wheel, and gooseneck type trailer hitches are common. A ball and socket arrangement may be used for light duty applications, while heavy duty applications may require a fifth wheel or gooseneck arrangement. A semi-trailer truck is an example of a heavy-duty application that might employ a fifth wheel or gooseneck trailer hitch.
A fifth wheel hitch may employ a ramp and skid plate that guides a hitch pin into a retaining slot defined by the hitch plate. Two spring-loaded locking arms may capture the hitch pin. In a common gooseneck type of hitch mechanism, a ball is typically mounted to the middle of a pickup truck bed and the socket mechanism is fastened to the trailer frame that reaches up, over and down into the pickup truck bed. Each of the fifth wheel and gooseneck types of hitching mechanisms allows the trailer limited roll and pitch, while allowing the trailer to rotate (yaw) significantly with respect to the tow vehicle when the tow vehicle turns while towing the trailer.
When hitching a trailer to a tow vehicle, a power supply of the trailer may also be connected to the tow vehicle. A power supply may comprise any type of supply that can perform work, such as an electrical supply, a hydraulic supply, a pneumatic supply, and/or a coolant supply, for example. The electrical, hydraulic, pneumatic, and/or coolant connection is typically manually made with a multi-conductor connector or connectors. One side of the connector may have a cable wired to the trailer and the other side of the connector may be wired to the tow vehicle. The connection may provide power for lighting and braking of the trailer.